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L F, TOOMEY NNDA C. S. DEMAREST.

MEANS FOR COMRULLENG ARTSFICIAL LINES.

APPLICAHUN man funi l5. w17.

1,308,726. izlvnvd July 1, 191i).

lying! yMag/74 v Y IENTORS ff [aw/fly (.2 (f, 123mm wf x BY ATTORNEY UNITED sTATEs PATENT OFFICE.

JOHN F. TOOMEY, 0F NEW YORK, AND CHARLES S. DEMAREST, 0F FLATBUSH, NEW YORK, ASSIGNORS TO AMERICAN TELEPHONE AND TELEGRAPH COMPANY, A

CORPORATION 0F NEW YORK.

MEANS FOR CONTROLLING ARTIFICIAL LINS.

Application tiled June 15, 1917.

T o all whom it may concern:

Be it known that we, JOHN F. TooMEY and CHARLES S. DEMABEsT, residing at New York and Flatbush, respectively, in the counties of New York and Kings, respectively, and Stato of New York, have invented certain Improvements in Means for Controlling Artificial Lines, of which the following is a specification.

This invention relates to telephone re peeters, and more particularly to arrangements for balancing the transmission circuit with which a telephone repeater may be associated.

In repeater organizations it is customary to construct a simple net-work adapted to simulate the impedance characteristic of the line with which the repeater is associated. W'hen, however, as is frequently the case,the line is composited in order that it may be used for telegraphie or signaling purposes in addition to its use as a telephone transmission circuit, it is necessary to provide means to balance the composite apparatus which is applied to the line. Moreover, if the line is used as one side of a phantom circuit, it is also nessary to provide means to balance the phantom apparatus applied to the line. Consequently', it is customary to supplement the simple net-work above referred to by an additional net-work to simulate the impedance of the composite apparatus and another'net-Work to simulate the phantom apparatus.

When the repeater is associated with the line, arrangements have been proposed whereby a balancing apparatus, constructed as above described, and suitable to balance .such line, is connected to the repeater. If, however.' the composite apparatus or the phantom apparatus should for any reason be ren'loved from the line, the balancing apparatus would not properly balance the line. It is ono of the objects of this invention to overcome this dillicnlay by providing means to control the connection or disconnection of the composite balancing set, or he phantom balancmpr set. to or from the repeater.

Further objects of the invention will be apparent from the followingr description, when read in connection with the accompanying drawing, the figure o! which con- Specitlcation cf Letters Patent.

Patented July 1, 1919.

smal No. 174,900.

stitntes a circuit diagram of one embodiment of the invention.

l Referring to the drawing, lines or trunks li] and L2 are shown terminating in jacks J, and JU. iVhile but two lines are shown it will bc understood that any number of lines` may similarly terminate in jacks bci'orc a rcpcatcr operator. A repeater R terminating in plugs P and P is provided for intcrconncctingincoming linee with outgoing lines. ihile for simplicity the repeater clcnicnts arc illustrated as being of the wellknown mechanical type, it is understood that the vacuum tube type or any other type of repeater univ be employed if desired. In practice a sn cicnt number of repeaters would ol course be provided to handle the lraliic. Artificial lines or net-worksll1 and N2 arc shown. said net-works to be adapted to balance the lines Ll and L2, respectively. Associated with the repeater is a composito balancing set S1, which is adapted to balance the .standard composite set which may be associated with any of the lines, a phantom balancing set Se being,lr also associated with thc repeater to balance the phantom apparatus which may be associated with a line, Noiunally the artificial lines N1 and N2 are disconnected froml the repeater. `Whcn the repeater is connected to a calling line by inserting the plug P in the jack of that line, the selectingr apparatus, herein shown as a set of selecting relays, is operated to select the artificial line correspondiner to the line to which the repeater is conlnectcd,y and such net-Work is connected t0 the reieater. At the same time connecting relays are energized to connect the balancing sots S, and S2 between the artificial line and the repeater. In accordance with this invention, the operation of these connecting relays may be prevented at will by inserting' an idlc plug such as P2 `in a controlling jack such as J3, L, J5, or J at the testboard. By this operation the connecting relay or relays corresponding to the jack in which the idle plug is inserted will be short-circnitcd, so that the balancing set controlled bv said relay or relays will not be connected. The selecting arrangement whereby the artificial line is associated with the repeater forms no part of this invention,- and while for purposes of illustration the selecting arrangement is of the relay type which is more fully illustrated and. claimedln the c0- pending application oil? C. S. Deniarest, Serial No. 174.886, filed June 15, 1917, it will be understood that any other type of Slectiu, r means may he used, such as for instance the` automatic selector .Switch arrangement disclosed aud claimed in a copeuding application of J. F. Toomey and (l. S. Demarest, Serial No. 174,889, filed June 15, 191.7, or the twin plugr arrangement shown vand claimed in the U. S. patent to J. FQ Toomey andlV. V. ll. Read, No. 1,277,274, patented Au rust 37, 1918.

l hile for purposes of illustration the arrangement for selecting an artificial line and for controllin the connection and disconnection of the Y as associated with only the answering end of thiI repeater, it will he understood that similar arrangements will be provided for the calling end of the repeater'.

With this brief description in mind the invention may now be fully understood from a description of the operation. Assuming that the line L, is to be connected through repeater R to some other line, the operator inserts the plug P in the jack J, and the plu(y P in the jack of the other line (not shown A circuit is now closed from ground to the windinr of relay 1, Sleeve contacts of jack J I an plugr P, winding of relay 2 to battery. Relay 2 is energized over this circuit, but relay 1 is marginal and does not receive sufficient current when in series with the high resistance Winding of relay 2 to energize its winding. The operator may now actuate a controlling key K, whereupon battery is connected over contact 8 of said key through a low resistance directly to the sleeve contact of plug P. Relay 1 no` receives sufiicient` current to energize ils winding and attracts its armature, thereby closing a circuit from ground, contact of relay 1. winding of relay 4, winding :md lower hack Contact of relay 5, back contact of relay (i, resistance 8, Contact 9 of key l( and contact of relay 2 Lo battery. Relays -l and 5 are energized over this circuit. Relay 5 at its lower front contact closes a locking circuit from ground, Contact of relay 1. winding of 4relay 4. winding and lower front contact of relay 5, resistance 10 and winding ol relay 11 to battery. Relay 11 is energized over this circuit, and then closes a circuit from battery over the front Contact of said rilay through windings of relays (l, G, and other similar relays (not shown) to ground. Relays (l, 6', etc., are energized thereby and operate to disconnect the selecting circuit from the winding of relays 5, 5. and similar relays (not slim-ln) so that no other connecting relay alancing sets has been shown can he operated. Relay o is maintained energized over the locliing circuit above traced. and at its upper contacts connects the artilieial line N, to the repeater R, so that the line L, is now balanced by said artificial line.

At. the same time that relay 5 was 'energized relay 4, which is in series with relay 5, was energized so that the following circuits were closed over ils contacts; from battery. left hand contact of relay 4, windings of' relays 1'2 and A13 in series to ground, and from baltery over the right hand contact of relay fl through the windings of relays 14; and 15 in series to ground. Relays 12, 1.3, 14 and 1 5 operate to interconnect the balancing sets S, and S2 between the artificial line N, and the repeater R, the circuit. extending 'from the terminals of artificial line N, over the upper contacts of relay 5, front contacts of relay 13, through the balancing set S,. over the contacts of relays 12 and 14, through the balancing set S, and over the contacts of relay 15 to the repeater.

It will non' be seen that the line L, 1s connected to the repeater and is balanced by an arrangement consisting of artificial line N a composite balancing set S, and a phantom balancing set SH. If, however, the composite apparatus (not shown) is disconnected from the line L, by an operator at the tcstboai'rd through the coaction of tht tip and ring contacts l not shown) of a plug P2 inserted in a jack J3. a condition is brought about whereby the windings of relays 12 and 13 are short-circuited over 'a circuit from ground, sleeve contacts of jack J, and plug 1) left hand contact of relay 4. to battery. The relays 12 and 13 will consequently not be energized and the composite balancing Set S, will not be connected in the balancing circuit. whicll extends from the terminals of artificial line N, over the upper contacts of relay 5 back contacts of relays 1.3 and 12, front contacts of relay 14, balancing set S2, front contacts of relay 15 to the repeater. In a similar manner, if the phantom apparatus should be disconnected from the line at the testboard, the operator at the testboard would insert a twin plug in jack` J 4, thereby short-circuiting relays 14 and 15 in a similar manner, so that said relays would be denergized and the phantom balancing set S, would not be connected in circuit. 4Tf the line L, has neither a eoinposite-balancin set nor a phantom balancing set, idle p ugs would be inserted in both jacks J and J4, so that all tour relays 12. 13, 14. and 15 would he short-rircuited.

Upon taking down the connection, relays 1 and 2 will be deinergized, the relay 1 at its contact opening the locking circuit through. relays +1, 5 and 11, which will be restored` to normal. Relay 4 Opens tho circuits of relays 12, 13, 14 and 15, thereby disconnecting balancing sets S1 and S2. Re-

lay 5 at its upper contacts disconnects the artificial line N1, while relay 11 opens the circuit previously traced through relays 6, 6', etc., so that said relays are deinergized and the circuits restored to normal.

lf the repeater R had been connected to the line L2 instead of L1 by inserting the plug P in the jack J2, upon operating the key K, relaysvl and 2 would have been encre-ized thereby closing circuits through ,re lays 4 and Said relays would have been locked up over a circuit from ground, front contact of relay 1', Winding of relay 4'. winding and lower front contact of relay I3', resistance 10 and winding of relay 11 to battery. Relay 5' at its upper contacts controls the conrwctingr of an artificial line N2 to the repeater in a manner similar to that by which relay 5 connected to the artiticial line N1. Relay 4 controls the circuits of relays 12'. 13', 14 and 15', to connect the balancing sets S1 and S2 in circuit so that the line LL, is balanced by means of a circuit including artificial line N2 and eX- tending from the terminals of said articial line over the upper contacts of relay 5', ["ront contacts ot relay 13' to set Si, over the front contacts of relays 12' and 14' to the set S2 and over the front contacts of relay 15' to the repeater. By inserting idle plugs in jacks J., or im the balancing'sets Sl or S2. respectively. may be disconnected from the cireuitin a manner similar to that already described in conectiou with jacks .L and Jr llpon taking down the connection the circuits will bey restored to normal in a manner similar to that already described.

By means of the arrangements above described. it will be seen that simple and efficient means for controlling the connection and disconnection of certain apparatus from a balancing circuit hasI been provided, and while the invention has been disclosed as embodied in a certain torni. it will be understood that it may be embodied in many widely different organizations Without departing from the spirit of the appended claims.

What is claimed is:

l. In combination with a transmission line and auxiliary apparatus associated therewith. a balancing arrangement therefor comprising an artificial line sin'lulatil'lg the transmission line. an auxiliary balancing set for simulating the auxiliary apparatus,

and switching meme for rendering the auxiliar balancing set inoperative at vwill.

A alancing arrangement comprising an artificial line for simulatin a transmission line, an auxiliary balancing set for simulating auxiliary apparatus associated with a transmission line, and switching means, controllable at will, for rendering saidfauxiliary balancing set operative and inoperative.

3. In combination, a transmission line, auxiliary apparatus associated therewith, a repeater, an artificial line for balancing said transmission line, an auxiliary balancing set for balancing said auxiliary apparatus, means for associating said artificial line and auxiliary balancing set with the repeater to balance the transmission line and auxiliary apparatus, and independent means, controllable at will, for governing the association of said auxiliary balancing set with the repeater.

Ai. In combination, a plurality of transmission lines, auxiliary apparatus associated therewith, artificial lines for balancing the transmission lines, a repeater for interconnecting the lines. an auxiliary balancing set for simulating said auxiliary apparatus. means operative when said repeater is connected to a transmission line to associate said auxiliary balancing set and an artificial balancin line suitable tobalance the .transmission hue with the repeater, and means controllable at will to prevent thel association of the auxiliary balancing set With the repeater.

5. ln combination, a plurality of transmission lines, auxiliary apparatus associated with certain of said lines. artificial lines for balancing said lines, a repeater for inter conmictim;r said lines, an auxiliary balancing set for simulating said auxiliary apparatus. means operative when the repeater is connected to a transmission line with which auxiliary apparatus is associated, to select an artificial line suitable for halanciner said trann'nission line and to connect suol articial line and said auxiliary balancing set to the repeater, and means to revent the connection of said auxiliary ba ancing set when the repeater is connected to a line with which no auxiliary apparatus is associated.

ln testimony whereof. We have signed our names to this specification this seventh day of June, 1917.

JOHN F. TOOMEY. CHARLES S. DEMAREST. 

